1. Field of the Invention
The invention relates to devices for covering the surface of a fluid such as a recreational swimming pool
2. Description of the Prior Art
It is well-known it requires an extensive amount of energy to maintain the temperature of a body of fluid, such as swimming pool water, at a desired temperature as the atmospheric temperature varies. In recognition of this need and the desire to limit the extent of evaporation from the surface of the fluid, many efforts have been made to provide a covering for pools and the like which are effective to cover the fluid surface to minimize the escape of heat and to prevent evaporation.
It has been long been recognize that curtain or web type covers are expensive to fabricate and install and can often be cumbersome to deploy. The mechanisms typically associated with deployment and retraction of such covers are often relatively expensive and can lend themselves to deterioration in the moist pool atmosphere and are subject to oxidization and require frequent maintenance and adjusting.
There have also been efforts to control the extent to which solar heat is absorbed in the body of fluid. In recognition of the benefits of solar heating to maintain pool temperature, many efforts have been made to provide solar blankets or the like with heat absorbing material for covering the surface of the pool. Examples of such blankets exist in U.S. Pat. Nos. 3,893,433, 3,453,666 and 3,072,920.
These prior art covers and blankets suffer the shortcoming that they are cumbersome to deploy and retract, a task which can be particularly challenging for irregularly shaped pool such as those with a kidney shape or the like not lending themselves to convenient coverage by a polygonal blanket.
In recognition of these shortcomings it has been proposed to provide for covering of the pool by thermally insulated buoyant balls, or the like, which are intended to be floated unto the pool surface and to cooperate in providing a thermal insulator across the pool surface. An insulated ball of this type is shown in U.S. Pat. No. 4,137,612 to Kelley. Spherical balls fail to cooperate in covering the entire pool surface.
In recognition of this shortcoming, it has been proposed to construct hollow balls with flat tangential surfaces disposed about the respective equators in expectation that the flat surfaces of adjacent balls might be engage one another and cooperate in covering the entire surface of the fluid body. Floats of this type are found in U.S. Pat. No. 3,998,204 to Fuchs et al. Balls of this type are relatively expensive to manufacture and problems are encountered from irregularities in the ball surfaces about their respective equators which often times cause them to ride up on top of each other during deployment thus preventing the respective balls from floating on the surface with their equators in the horizontal plane thereby preventing total and complete pool coverage.
Other efforts to provide for full surface coverage by individual floats led to the development of a blanket device made up of a plurality of individual cells, termed coverites in the form individual sealed bags of polyethylene plastic including a combination of water and translucent gas of air, with the walls of the individual coverites being flexible in anticipation that the coverites, when engaging one another, conform peripheral walls of adjacent neighbor's conform to one another to thereby cooperate in covering the surface of the pool. While an interesting concept, such devices would be relatively expensive to manufacture and have not been well accepted in the marketplace.